Struct Scalar 

pub struct Scalar(/* private fields */);

P-521 scalar value for use in elliptic curve operations. Represents integers modulo the curve order n. Used for private keys and scalar multiplication. Automatically zeroized on drop for security.

Implementations

impl Scalar

pub fn new(data: [u8; 66]) -> Result<Self>

Create a canonical non-zero scalar from raw bytes.

Private keys, nonces, and serialized signature components must be in 1..n. Non-canonical 528-bit encodings are rejected rather than reduced.

pub fn from_bytes_reduced(data: [u8; 66]) -> Self

Interpret a 528-bit encoding modulo the group order, including zero.

P-521 scalars use a 66-byte encoding. This constructor is intended for standards-defined mathematical intermediates such as ECDSA hash and x-coordinate reduction. Use Self::new for private scalars, nonces, and serialized signature components, where zero is invalid.

pub fn from_secret_buffer( buffer: SecretBuffer<P521_SCALAR_SIZE>, ) -> Result<Self>

Create a scalar from an existing SecretBuffer. Performs the same canonical validation as new() but starts from a SecretBuffer instead of a raw byte array.

pub fn as_secret_buffer(&self) -> &SecretBuffer<P521_SCALAR_SIZE>

Access the underlying SecretBuffer containing the scalar value

pub fn serialize(&self) -> SecretBuffer<P521_SCALAR_SIZE>

Serialize the scalar to protected exact-size storage. Returns the scalar in big-endian byte representation. The output clears itself on drop. Callers that deliberately expose a public signature component may copy from its borrowed slice.

pub fn deserialize(bytes: &[u8]) -> Result<Self>

Deserialize a scalar from bytes with validation. Parses bytes as a big-endian scalar value and ensures it’s in the valid range for P-521 operations.

pub fn is_zero(&self) -> bool

Check if the scalar represents zero. Constant-time check to determine if the scalar is the additive identity (which is invalid for most cryptographic operations).

pub fn add_mod_n(&self, other: &Self) -> Result<Self>

Add two scalars modulo the curve order n

pub fn sub_mod_n(&self, other: &Self) -> Result<Self>

Subtract two scalars modulo the curve order n

pub fn mul_mod_n(&self, other: &Self) -> Result<Self>

Multiply two scalars modulo the curve order n. Uses constant-time double-and-add algorithm for correctness and security. Processes bits from MSB to LSB to ensure correct powers of 2.

pub fn inv_mod_n(&self) -> Result<Self>

Compute multiplicative inverse modulo n using Fermat’s little theorem a^(-1) ≡ a^(n-2) (mod n). Left-to-right binary exponentiation.

pub fn negate(&self) -> Self

Compute the additive inverse (negation) modulo n Returns -self mod n, which is equivalent to n - self when self != 0 Returns 0 when self is 0

Trait Implementations

impl Clone for Scalar

fn clone(&self) -> Scalar

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Scalar

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Drop for Scalar

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.

impl Zeroize for Scalar

fn zeroize(&mut self)

impl ZeroizeOnDrop for Scalar